DE3020986A1 - COATING AGENTS BASED ON EPOXY RESINS - Google Patents

Abstract

1. Coating agents comprising epoxy resins and hardeners based on bisphenol A and/or bisphenol F epoxy resins and polyamines, polyamino adducts and/or polyaminoamides, characterised in that they additionally contain ketone resins.

Description

Coating agents based on epoxy resins

Two-component epoxy resin systems that cure at room temperature usually consist of epoxy resins on the Based on bisphenol A and / or bisphenol P, which are crosslinked with polyamines, polyamine adducts or polyamine amides will. The reaction can optionally be accelerated by using phenolic compounds.

Coating materials of this type are characterized by very good mechanical properties and chemical resistance. Their use is trc-tz these good ones Properties are limited because their weather resistance is unsatisfactory and their price is relatively high. The movies are degraded on the surface when exposed to weathering, which is expressed, among other things, in a strong chalk. The superficial Pilm degradation leads to the poor quality of epoxy resin-based pole paints on weathered epoxy resin films be liable.

It is known that certain properties and economics of two-component epoxy resin systems

and / or by blending with calibrators resins, such as. B. Coumarone-indene resins, or with coal tar or coal tar pitch • can be favorably influenced. By Although these measures improve the economy and, under certain circumstances, other properties, the However, the lack of unsatisfactory weather resistance has not been remedied, since those proposed and used since then Blending agents for epoxy resins are degraded to a greater or lesser extent in the event of weathering and / or with Epoxy resins are not homogeneously compatible.

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It has been found that the surface film degradation when coating materials based on epoxy resins are exposed to weathering is significantly reduced and the ability to be painted over can be significantly improved if the customary two-component epoxy resin systems are mixed with ketone resins which are compatible with epoxy resins. The proportion of ketone resins in the binder (epoxy resin + hardener - ketone resin) can be around 20 to 70% by weight. The most favorable properties are obtained with a ketone resin content of ¹ JO to 60 %.

The invention therefore provides a coating composition based on epoxy resins and hardeners, which thereby is characterized in that they additionally contain ketone resins.

The ketone resin content in the binder is 20 to 70% by weight , preferably 40 to 60% by weight .

The chemical resistance, the mechanical properties and the hardening are not impaired in this area, on the other hand, the weather resistance and the paintability of weathered films are significantly improved because the superficial film degradation of common two-component epoxy resin systems is reduced by the addition of ketone resin.

The inventive addition of ketone resins to two-component epoxy resin systems is possible with systems that use epoxy resin condensation products of bisphenol A and / or bisphenol F and those with polyamines, polyamino adducts or polyaminoamides are crosslinked. With-

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use of phenolic accelerators is beneficial. Furthermore, the fillers, dyes, pigments and solvents customary in this field can optionally also be used. Suitable ketone resins are those
Cyclohexanone / formaldehyde and especially cyclohexanone based.

The use of ketone resins with liquid epoxy resins is particularly advantageous. This leads to coating materials which in addition to their very good weather resistance and paintability because of their high solids content are very economical and environmentally friendly because of their low solvent content.

As examples of the coating compositions according to the invention the following formulations are mentioned:

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Example 1 resin component

18 wt -.% Solid epoxy resin based on bisphenol A-based

Epoxy equivalent weight 500) 30 wt .-% ketone 16 wt -.% Methyl isobutyl ketone 16 wt .-% xylene 80 wt .- #

Hardener component

8 wt -.% Polyamlnoarnid based on dimeric fatty acid and

Triethylenetetramine (amine number approximately i * wt .- # Benzyl alcohol 8 wt -.% Xylene 20 wt .-%

Finished material

80 wt. Resin component 20 wt -.% Hardener component

Example 2 resin component

20 wt -.% Liquid epoxy resin based on bisphenol A-based

(Epoxy equivalent mass approx. 200) 35 % by weight ketone resin

5 wt -.% Methyl isobutyl ketone, 1 5 parts by weight xylene 75 parts by weight f-J?

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Hardener component

7 wt. cycloaliphatic polyamine (3.3 ^f -dimethyl- * l, 4 ^f

diamino-dicyclohexyl-methane, amine number approx. 470) 10 wt. Nonylphenol

8 wt. Xylene 25 wt.

75 wt. JS resin component 25 wt. Hardener component

Example 3 Resin Component

29 wt. liquid epoxy resin based on bisphenol A

(Epoxy-squivalent mass approx. 200) 13 Gew.-JJ ketone resin (condensation product from cyclohexanone

and formaldehyde) 2 wt .- /? Ethyl glycol 6 wt. 5? Xylene

Hardener component

23 wt. Polyaminoamide based on dimeric fatty acids and

Triethylenetetramine (amine number approx. 240) 15% by weight? Nonylphenol 2 wt. Ethyl glycol 10 wt. Shellsol A

Finished material

50 wt. Resin component 50 wt. Hardener component

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ORIGINAL INSPECTED

Example 4 Resin Component

14 wt .- ^ liquid epoxy resin based on bisphenol A (Epoxy equivalent mass approx. 200)

42 wt -.% Ketone resin (condensation product of cyclohexanone) 24 wt -.% Xylene

Hardener component

5 wt. JS cycloaliphatic ^ polyamine (3,3 '-Dimethyl-4,4' -

⁴ diamino-dicyclohexyl-methane, amine number approx. 47'O)

4 wt -.% Cresol

11 wt -.% Xylene

Finished material

80 wt .-% resin component 29 wt -.% Hardener component

A comparison of the coating compositions according to the invention compared to epoxy resins without ketone resin content showed the following results:

Steel plates were painted and, after drying, were left outdoors for 5 months in a normal climate. For comparison were Also tested: pure epoxy resin paints of the same composition (without ketone resin), blended with coumarone-indene resins Epoxy resin paints and epoxy resin paints blended with coal tar pitch.

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The tests have shown that the epoxy resin-ketone resin combinations according to the invention after outdoor exposure Chalk off significantly less than all of the systems tested for comparison.

b) paintability

The epoxy resin-ketone resin combinations and those under a) listed systems (pure epoxy resin, epoxy resin + coumarone-indene resin, epoxy resin + coal tar pitch) were painted over with itself after three months of exposure to the price. After another month of price weathering, the intermediate adhesion of the last coats on the weathered coats checked. It has been shown that with all epoxy resin-ketone resin combinations according to the invention, the pole paints on the previous weathered paints were liable, while with all other systems tested for comparison there was no intermediate liability in this test could be determined.

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Claims (1)

LECHLER CHEMIE GMBH
Patent claims Coating agents based on epoxy resins and hardeners, characterized in that they additionally Contain ketone resins. 2 »Coating agent according to claim 1, characterized net that the proportion of ketone resin in the binder 20 to 70 wt .- 5? amounts to. 3. Coating agent according to claim 2, characterized in that the proportion of ketone resin in the binder 40 to Is 60% by weight. 130050/0300 ORIGINAL INSPECTED